25 \medskip

    27 \noindent

    28 {\bf Warning:} This draft is draftier than you might expect.

    29 More specifically,

    30 \begin{itemize}

    31 \item Some sections are missing.

    32 \item Many sections are incomplete.

    33 In some cases the incompleteness is noted, in some cases not.

    34 \item Some sections have been rewritten, but the older, obsolete version of

    35 the section has not been deleted yet.

    36 \item Some sections were written nearly two years ago, and are now outdated.

    37 \item Some sections have not been proof-read.

    38 \item There are not yet enough citations to similar work of other people.

    39 \end{itemize}

    40 Despite all this, there's probably enough decipherable material

    41 here to interest the motivated reader.